From 39292638afb1e2d9ce535936caac279b620b29c1 Mon Sep 17 00:00:00 2001 From: Furquan Shaikh Date: Thu, 4 Sep 2014 15:33:00 -0700 Subject: [PATCH] libpayload arm64: Initialize and enable MMU What this change does: 1) Initialize limited page tables as soon as we jump into libpayload. Basically two ranges are initialized. One is for the BASE_ADDRESS and other is for the coreboot_tables. With page tables initialized and MMU enabled, we jump into code to parse coreboot tables. 2) Once coreboot tables are parsed and we have complete picture of the memory, we perform a complete page table initialzation and enable MMU and then jump to payload. Additionally, we also: 1) Initialize DMA memory on our own depending upon the memory map. It ensures that the DMA buffer is placed in 32-bit memory. CQ-DEPEND=CL:216826 BUG=chrome-os-partner:31634 BRANCH=None TEST=Compiles successfully and we are able to start execution of libpayload in EL2 and reach kernel login prompt Change-Id: I8a6203e465868bc2a3e5cc377e108f36cc58e2fa Signed-off-by: Patrick Georgi Original-Commit-Id: 7695bb7afe34ea460282125a0be440e8994b01e4 Original-Change-Id: Ie0f47b7759d4ac65a6920f7f2f7502b889afda6d Original-Signed-off-by: Furquan Shaikh Original-Reviewed-on: https://chromium-review.googlesource.com/216824 Original-Reviewed-by: Aaron Durbin Original-Tested-by: Furquan Shaikh Original-Commit-Queue: Furquan Shaikh Reviewed-on: http://review.coreboot.org/8792 Tested-by: build bot (Jenkins) Reviewed-by: Stefan Reinauer --- payloads/libpayload/arch/arm64/main.c | 64 +++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) diff --git a/payloads/libpayload/arch/arm64/main.c b/payloads/libpayload/arch/arm64/main.c index 6b45a018c2..4561e2e08d 100644 --- a/payloads/libpayload/arch/arm64/main.c +++ b/payloads/libpayload/arch/arm64/main.c @@ -29,6 +29,7 @@ #include #include +#include unsigned int main_argc; /**< The argc value to pass to main() */ @@ -48,6 +49,64 @@ static int test_exception(void) return 0; } +/* + * Func: pre_sysinfo_scan_mmu_setup + * Desc: We need to setup and enable MMU before we can go to scan coreboot + * tables. However, we are not sure what all memory regions to map. Thus, + * initializing minimum required memory ranges + */ +static void pre_sysinfo_scan_mmu_setup(void) +{ + uint64_t start = (uint64_t)&_start; + uint64_t end = (uint64_t)&_end; + + /* Memory range 1: Covers the area occupied by payload */ + mmu_presysinfo_memory_used(start, end - start); + + /* + * Memory range 2: Coreboot tables + * + * Maximum size is assumed 2 pages in case it crosses the GRANULE_SIZE + * boundary + */ + mmu_presysinfo_memory_used((uint64_t)get_cb_header_ptr(), + 2 * GRANULE_SIZE); + + mmu_presysinfo_enable(); +} + +/* + * Func: post_sysinfo_scan_mmu_setup + * Desc: Once we have scanned coreboot tables, we have complete information + * about different memory ranges. Thus, we can perform a complete mmu + * initialization. Also, this takes care of DMA area setup + */ +static void post_sysinfo_scan_mmu_setup(void) +{ + struct memrange *ranges; + uint64_t nranges; + struct mmu_ranges mmu_ranges; + struct mmu_memrange *dma_range; + + /* Get memrange info from lib_sysinfo */ + lib_sysinfo_get_memranges(&ranges, &nranges); + + /* Get memory ranges for mmu init from lib_sysinfo memrange */ + dma_range = mmu_init_ranges_from_sysinfo(ranges, nranges, &mmu_ranges); + + /* Disable mmu */ + mmu_disable(); + + /* Init mmu */ + mmu_init(&mmu_ranges); + + /* Enable mmu */ + mmu_enable(); + + /* Init dma memory */ + init_dma_memory((void *)dma_range->base, dma_range->size); +} + /** * This is our C entry function - set up the system * and jump into the payload entry point. @@ -57,12 +116,17 @@ void start_main(void) { extern int main(int argc, char **argv); + pre_sysinfo_scan_mmu_setup(); + /* Gather system information. */ lib_get_sysinfo(); #ifndef CONFIG_LP_SKIP_CONSOLE_INIT console_init(); #endif + + post_sysinfo_scan_mmu_setup(); + printf("ARM64: Libpayload %s\n",__func__); exception_init();